Analysis of Scaling‐Up Resistances from Leaf to Canopy Using Numerical Simulations

Abstract

A multi-layer model, combining Lagrangian dispersion at the canopy level with Ohm's Law analogy at the leaf level, was used in numerical simulations to assess the leaf-to-canopy scale translation of surface resistances. The model produced unique profiles of fluxes and scalar concentrations that satisfied both the dispersion and leaf models. Environmental factors and canopy architecture were varied, and stomatal conductance was simulated using either a simple relationship with net radiation or the Ball and Berry model to account for feedback mechanisms. Results showed that, when the assumptions of the Penman-Monteith equation were met, scaled-up leaf conductance closely matched the bulk canopy conductance. However, as the scenarios modeled departed from the ideal conditions of Penman-Monteith, the agreement decreased. In particular, correct estimation of the aerodynamic resistance, through correct parameterization of the roughness length for sensible heat, was identified as a key issue.

Utilizing systems biology to unravel stomatal function and the hierarchies underpinning its control

“…To this end, the existing models of gs for single leaves have been scaled up to the level of canopy, often performed following the big-leaf top-down approach (Baldocchi et al 1991). To this end, there is the alternative of determining the canopy gs as the sum of the conductance of individual leaves (see Blonquist et al 2009) or following the Penman-Monteith equation (Monteith 1981;Furon et al 2007). The former could be used to combine multiple large-scale models of illuminated and shaded leaves, with the idea of expanding the applicability of the large-scale models on the level of canopy, a much desired extension of the applicability of constraint-based approaches.…”

“…) or following the Penman–Monteith equation (Monteith ; Furon et al . ). The former could be used to combine multiple large‐scale models of illuminated and shaded leaves, with the idea of expanding the applicability of the large‐scale models on the level of canopy, a much desired extension of the applicability of constraint‐based approaches.…”

Evaporative losses from a common reed‐dominated peachleaf willow and cottonwood riparian plant community

“…Direct application of this approach relies on measured direct feedback from the individual plant species and measured microclimatic and environmental parameters. This approach involves measurement or modeling of stomatal resistance ( r L ) and other primary environmental variables and requires scaling up r L to canopy resistance ( r c ) using microclimatic and plant factors such as leaf area index (LAI) for sunlit and shaded leaves, solar zenith angle, direct and diffuse solar radiation above and within the canopy, and other environmental parameters [ Kaufman , 1982; Jarvis and McNaughton , 1986; Rochette et al , 1991; Lhomme et al , 1998; Jones , 1992; Tourula and Heikinheimo , 1998; Furon et al , 2007; Irmak et al , 2008; Irmak and Mutiibwa , 2010; Mutiibwa and Irmak , 2011]. The scaling‐up process primarily relies on scaling up r L to r c as a function of solar radiation, net ration, or photosynthetic photon flux density (PPFD).…”

Estimating Transpiration from Turfgrass Using Stomatal Conductance Values Derived from Infrared Thermometry

“…The commonly used Penman–Monteith equation is an example of a big‐leaf approach. Furon et al (2007) examined the Penman–Monteith equation and found big‐leaf resistance (reciprocal of canopy conductance) to be similar to canopy resistance from scaled‐up leaf resistance. However, there are two major differences between the proposed approach and the Penman–Monteith equation.…”